3.4 dies after 1-3 seconds after start

okay so my friends 3.4 97 4Runner just dies on him driving about 30 on the highway. now it dies after start up. it will run about 1-3 seconds it will run. sounds like it gonna go then turns to a real rough idle and can hear in the airbox like its grasping for air then it dies.

i can hear the fuel pump whine and start up.
changed the fuel filter and there was still pressure in the system
changed the MAF sensor.
Cleaned out the Idle Control Valve
vacuum lines seem to all be in place.

im kind of stumped.
could it be the CAMSHAFT position Sensor?
any ideas help.

 

i tried that. still does the same thing. i believe these engines need the MAF plugged in and working to run.
ill try it again.

 

Go to auto zone and rent a fuel pressure gauge. See what kind of pressure you got.
Remove top timing belt cover and check cam timing also. No codes or check engine light?

 

The ECU needs a signal back from the ignition to keep firing the injectors and keep the fuel pump on. Ignition needs crank and cam sensors signals to fire the spark plugs.

Are there any codes? Try looking at live data from the code scanner to gain any insight too.

 

They've changed ecus lots more than that, 95,96,97,98-99,00,01-02,03,04 ecus don't last long in the Toyota world haha

 

It’s not throwing any codes at all. I’ll try Check the fuel pressure. I really don’t think that’s it though because it’s fairly new

 

No light pretty much says a fuel delivery problem.

unless your light is burned out ?

It does come on with ignition switch on ?

 

It’s come on before on his truck. So it’s not burned out. Maybe we will just swap the fuel pump out

 

It your project do what works best for you

Know going in just a new pump might not solve the problem.

Best of luck

 

Maybe it is throwing a CEL but it's not running long enough to trigger it? 1-3 seconds before dying is pretty quick. If you can plug in a code scanner or have a shop do it and see if it's throwing a code or a pending code (which wouldn't trigger the CEL) maybe it will help point you in the right direction.

 

Are you throttling at start up? Try giving it some throttle as soon as start up occurs to see if it will run under throttle. If so, if it continues to die at idle, I would suspect Idle Air Control valve. I know initial post said IAC was cleaned, but I had an IAC go bad before and was similar - easy start up but dies right away. I'm so used to not throttling newer cars that it took a while to figure out.

Let us know what you figure out, good luck!

 

Thanks for all the input guys!!
It will die even when throttling at start up too. When I feel the line it doesn’t feel like a steady flow of fuel. I’m thinking it’s the pump after all not giving enough pressure. There is no valve on the fuel rail to test pressure.
Is there a valve anywhere? I can’t find one.

 

When you start it have someone beat on the gas tank with a bar or rubber mallet. Make sure your hitting the tank and not skid. If pump has low pressure usually it will revive the pump enough for the motor to run. Then you know the pump has failed.

If there are plans to ever supercharge its a good time to upgrade the fuel pump to a 190lph. It can handle it stock. I recommend an oem pump from a Mitsubishi lancer evo 8/9. Can find them used cheap sometimes and they are high quality denso. But you also want the harness and plug to make splicing easy. Or you can go with a walbro but they tend to fail and whine pretty loud.

 

Just beat it and it was running a little longer than normal. Gonna pick up a fuel pump tomorrow!! Thanks!

 

so it ended up being the wiring from the plug to the fuel pump. the gasoline ate up the old set up so i made up a new wiring harness and that did the trick and changed the pump sine we where in there. thanks guys for all the help and suggestions.